When cancer research is conducted on a particular substance, scientists begin by observing the effect of that substance on specific types of cancer cells in a lab. If the substance has a significant impact in causing the death of those cancer cells, future research may be warranted to see if it is a potential cancer treatment.

In a laboratory setting, horse chestnut extract has shown cancer-fighting effects on cells related to leukemia, cervical cancer and breast cancer. The most drastic of these were Jurkat cells, used to test a type of cancer known as acute T-cell leukemia, in which the lab tests found a cell death rate of nearly 94 percent.